The present invention relates to an illumination system for use with machine vision systems, such as optical and barcode scanning systems. More particularly, it relates to a system for focusing light on a line or area in which a machine vision system collects image data.
In order to increase accuracy and maintain consistency in the data collected by machine vision systems it is important to have a direct source of light to fully illuminate the area being scanned (hereinafter the “illumination area”). In the case of a linear scanner, a narrow illumination line is sufficient. For area-array based scanning equipment such as video cameras, it is necessary to illuminate a wider area. As used in this application and the appended claims, the term “illumination area” should be understood as including both area and line illumination. Such illumination systems have traditionally consisted of either direct illumination or a combination of direct and reflected illumination, in which light energy is focused onto an illumination area using a reflector. Systems using a combination of direct and reflected light typically use incandescent or HID light sources. Such systems are not ideal because they are somewhat inefficient in that they consume energy at a relatively high rate and generate a large amount of heat.